Importance Breakdown of Harrison's 2016 U.S. Open Upset of Milos Raonic

On the first day of Round 2 of the 2016 U.S. Open, an American served up what could turn out to be one of the biggest upsets of the tournament. Ryan Harrison, ranked 220 in the world and known mostly for a streak of unlucky draws at Grand Slams, defeated huge-hitting World No. 6 Milos Raonic 6-7 (4), 7-5, 7-5, 6-1.

Harrison might have been the crowd favorite going into the match, but he was also the massive underdog. FiveThiryEight’s U.S. Open model gave Harrison just a 9% chance of pulling out a win.

Given those odds, I was curious to see how Harrison turned the match in his favor. Below is a plot charting the American’s point-by-point win expectation, which updates Harrison’s pre-match odds given the current score. You can see that, even when going into the fourth set and having 2 sets under his belt, Harrison was never a sure bet. In fact, it wasn’t until breaking Raonic in the fourth game of the fourth set that Harrison finally took the win advantage.

Why are these predictions so much against Harrison, even when he had more sets on the board than Raonic?

There are a few reasons. First, the predictions assume that each player has a constant chance of winning a point on serve. And the serve predictions are based on the expected win chance of 91% for Raonic and a 50% gap between Harrisons percentage of points won on serve and his points won on return, as this is how he has performed on hard courts against top 10 players this year. The predictions don’t consider player injuries (which clearly was an issue with Raonic) and don’t update the serve ability based on the way things are trending during the match. Instead, they tell us what we would expect the outcome to me from the current score if both players were playing to their expected abilities. Still a useful reference, I think.

As in another match review, I have also provided the point-by-point importance. It is interesting that this chart suggests that the tighest sets were the first and third, reflecting the fact that the match was really not close by the end of the third set.

It wasn’t perhaps the way Harrison would want to earn his way into the third round of the U.S. Open but he has earned it nonetheless. And no matter what happens from this point on, many will look back on this match and agree with Steve Tignor that it was “a win of a career”.

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